The 'oh, who cares' 1st half of May boring ass pattern banter thread

[CoastalWx]

The last two springs (2011 and 2012) are null and void and cannot be considered BSE now.

Yeah they were great Springs, but every spring can't be the best...unless you live in lala land like he does.

I love 60s-70s. Perfect wx,

[dendrite]

The dewpoints at ASOS stations are considered to be more accurate to the larger scale boundary layer conditions versus a PWS that sits over florishing plant life and that also may be protected a bit from the mixing of the midday atmosphere.

 

The reading isn't "Wrong" per say on the PWS, its just not very representative of the larger scale surroundings. Its why we don't get that excited during severe weather season when a PWS has a dewpoint of 71F but all the ASOS stations within 50 miles are in in the lower 60s.

The ASOS sensors are much more accurate with dew readings than the home stations anyways. The home sensors work very well for the money though. The Davis hygrometer has an accuracy of +/- 3% from 0-90% and +/- 4% from 90-100%. A high end Vaisala HMP155 with HUMICAP technology is +/- 1.0% and 1.7% for those ranges respectively.

I belive the ASOS sensors still use a chilled mirror sensor. Also, just like temp, the use a 5 min running average to determine the dewpoint each minute so random spikes will get washed out.

[joey2002]

Could be a perfectly average day at BDL.  (72/48)  The low was 48 this morning, and the hourly high so far is the current temp of 71. 

[Ginx snewx]

They might be more accurate reading the dews but there is no doubt all that asphalt skews the readings at some asos

[tamarack]

I'm confident that those transpirationally-fed dews are accurate, but probably represent only the lowest 50 yards of the atmosphere, where wx is felt but not where it's made.  (Midwest corn-dews may affect a taller layer, but I think the principle remains valid.)

[Ginx snewx]

I'm confident that those transpirationally-fed dews are accurate, but probably represent only the lowest 50 yards of the atmosphere, where wx is felt but not where it's made. (Midwest corn-dews may affect a taller layer, but I think the principle remains valid.)

yep

[TWCCraig]

They might be more accurate reading the dews but there is no doubt all that asphalt skews the readings at some asos

 

Agree. My nearest ASOS has that problem, it usually averages a dew point error too dry of about 2 to 4 degrees.

 

You can see here: http://weather.gladstonefamily.net/site/KISP that while all the other sensors are accurate compared to the KISP analysis, the dew point is inaccurate. You can also find out about the accuracy of your local ASOS by typing it in replace of KISP in the address bar.

[dendrite]

They might be more accurate reading the dews but there is no doubt all that asphalt skews the readings at some asos

I would guess very few. You would have bigger issues with temperature than dewpoint imo in that case. We joke about ASOS being on a tarmac, but the vast majority are sited over grass fields and away from the runways. I think what makes their dews lower is the fact that they are more exposed...betterwind obs equal better sfc mixing. On those light wind, steamy summer afternoons in the countryside, the moisture from the evapotranspiration just pools up below the tree tops until you get some decent winds to mix it out. We can argue all day if those readings are "real" or not, but with proper siting they wouldn't be.

[Ginx snewx]

I would guess very few. You would have bigger issues with temperature than dewpoint imo in that case. We joke about ASOS being on a tarmac, but the vast majority are sited over grass fields and away from the runways. I think what makes their dews lower is the fact that they are more exposed...betterwind obs equal better sfc mixing. On those light wind, steamy summer afternoons in the countryside, the moisture from the evapotranspiration just pools up below the tree tops until you get some decent winds to mix it out. We can argue all day if those readings are "real" or not, but with proper siting they wouldn't be.

Tamarack hit the nail on the head though.

[dendrite]

Tamarack hit the nail on the head though.

I said the same thing. But my point stands that almost every home station doesn't have proper siting for ASOS standards.

[CoastalWx]

When you have winds continously advecting in air towards an ASOS, I find it difficult to think a tarmac has any substantial effect regarding dews..if at all.

[Ginx snewx]

Agree. My nearest ASOS has that problem, it usually averages a dew point error too dry of about 2 to 4 degrees.

You can see here: http://weather.gladstonefamily.net/site/KISP that while all the other sensors are accurate compared to the KISP analysis, the dew point is inaccurate. You can also find out about the accuracy of your local ASOS by typing it in replace of KISP in the address bar.

interesting pretty much as much as Davis. How do they know what the correct is?

[Ginx snewx]

When you have winds continously advecting in air towards an ASOS, I find it difficult to think a tarmac has any substantial effect regarding dews..if at all.

Nobody lives on a tarmac....? Lol

[TWCCraig]

interesting pretty much as much as Davis. How do they know what the correct is?

 

They take the average of other surrounding CWOP/AWOS/ASOS/MADIS stations to make an "analysis", then compare it to KISP.

 

By default, the longer analysis periods display graphs that show the long term performance of this station. The graphs show the mean error over time, and include error bars which are one standard deviation long. This provides an easy way to see if there are any underlying trends in the data. Note that a 'step' in your data does not (necessarily) mean that something happened to your station. It could mean that another station came online in the local area, and they are changing the analysis.

The analysis is performed by MADIS. This web page just provides visualization of the data that MADIS produces.

 

[CT Rain]

Is that what the "Ugh" was for at the end of his post?

I took it as he's annoyed because he cant trust his dew as much as he'd like.

Eitherway, Ryan looks like a decent spot for acceptable wind obs except the 90 degrees occupied by that tree.

 

Yeah the thing with the dews is that while the dew point actually is accurate for its specific location you're comparing apples and oranges with the ASOS. 

[dendrite]

Agree. My nearest ASOS has that problem, it usually averages a dew point error too dry of about 2 to 4 degrees.

 

You can see here: http://weather.gladstonefamily.net/site/KISP that while all the other sensors are accurate compared to the KISP analysis, the dew point is inaccurate. You can also find out about the accuracy of your local ASOS by typing it in replace of KISP in the address bar.

MADIS analysis can be off sometimes. We don't know which stations it was using for the analysis anyways. I think the purpose of it is to weed out the extremely egregious readings.

MADIS almost always has issues with MWN and a home station out here on an island on Lake Winni (Black Cat Island). Obviously MWN is 6kft+ up and the island station is water-locked so MADIS thinks it reads too cold this time of year during the day. I'll trust the ASOS readings.

[CT Rain]

I would guess very few. You would have bigger issues with temperature than dewpoint imo in that case. We joke about ASOS being on a tarmac, but the vast majority are sited over grass fields and away from the runways. I think what makes their dews lower is the fact that they are more exposed...betterwind obs equal better sfc mixing. On those light wind, steamy summer afternoons in the countryside, the moisture from the evapotranspiration just pools up below the tree tops until you get some decent winds to mix it out. We can argue all day if those readings are "real" or not, but with proper siting they wouldn't be.

 

This is exactly right. As much as everyone screams about tarmac and asphalt if you've ever flown out of say BDL you realize that there's a whole lot more open grass than some big paved over monstrousity.

 

The difference is exactly what you said. When you're in a wide open area away from trees and other obstructions you're able to increase the amount of turbulent mixing that will keep the dews more constant and more representative of the free atmosphere. Surrounded by trees, houses, fences, etc. you can get very stagnant air near the ground that isn't properly mixed/ventilated.

 

I can also notice the difference with my winds. My anemometer is about 30 ft up but blocked by trees and a hill to my west. Winds are much lower than at the nearby ASOS sites which shows that there's much less momentum transfer through turbulent mixing here than there is at HFD or BDL. It's no surprise that the dew point sensor is skewed by the ET from the grass/plants when not properly ventilated.

[TWCCraig]

MADIS analysis can be off sometimes. We don't know which stations it was using for the analysis anyways. I think the purpose of it is to weed out the extremely egregious readings.

MADIS almost always has issues with MWN and a home station out here on an island on Lake Winni (Black Cat Island). Obviously MWN is 6kft+ up and the island station is water-locked so MADIS thinks it reads too cold this time of year during the day. I'll trust the ASOS readings.

 

True, however, considering that all other sensors at KISP are running almost perfect with the analysis, and the dew point isn't, it makes me think if there's something wrong with the dew point sensor. There are times when there's a 5, 6 or even 7 degree difference between the ASOS and the analysis, that can't all be MADIS.

[CT Rain]

True, however, considering that all other sensors at KISP are running almost perfect with the analysis, and the dew point isn't, it makes me think if there's something wrong with the dew point sensor. There are times when there's a 5, 6 or even 7 degree difference between the ASOS and the analysis, that can't all be MADIS.

 

That's probably because almost all the MADIS sites are in neighborhoods and locations with much higher roughness lengths than a properly sited ASOS away from trees, buildings, obstructions. That's why KISP will get much higher wind gusts than any of those MADIS sites on a well mixed day. 

 

It's probably more a function of all the MADIS sites being improperly sited than it is the KISP dew point sensor running warm.

 

I've noticed that some of the AWOS sites in CT that are privately owned by the airports (SNC and LZD come to mind) can have some funky high dew points since they're not as well sited as an ASOS like BDR and BDL. I think airports are really good locations for these wx instruments since they're in very flat areas that are quite open and away from terrain/obstructions. What's good for planes is good for weather readings.

[dendrite]

True, however, considering that all other sensors at KISP are running almost perfect with the analysis, and the dew point isn't, it makes me think if there's something wrong with the dew point sensor. There are times when there's a 5, 6 or even 7 degree difference between the ASOS and the analysis, that can't all be MADIS.

I don't follow ISP dews so I wouldn't know if something stands out, but in general ASOS readings are pretty damn good. I've seen some funky readings with AWOS before though, but of course ISP is ASOS.

Isn't KISP a little bit inland over LI? The more coastal sites factored into the analysis may be bumping up the analysis dew. Also, if ISP radiates well they will probably radiate down to a pretty low tt/td saturation by sunrise. My guess is FOK probably is too low in the eyes of MADIS too.

[dendrite]

That's probably because almost all the MADIS sites are in neighborhoods and locations with much higher roughness lengths than a properly sited ASOS away from trees, buildings, obstructions. That's why KISP will get much higher wind gusts than any of those MADIS sites on a well mixed day. 

 

It's probably more a function of all the MADIS sites being improperly sited than it is the KISP dew point sensor running warm.

 

I've noticed that some of the AWOS sites in CT that are privately owned by the airports (SNC and LZD come to mind) can have some funky high dew points since they're not as well sited as an ASOS like BDR and BDL. I think airports are really good locations for these wx instruments since they're in very flat areas that are quite open and away from terrain/obstructions. What's good for planes is good for weather readings.

Creepy...we both described AWOS dews as "funky"...lol.

[ORH_wxman]

There's a reason that ASOS standards are so high and that we don't use backyard weather stations for most of the input into computer models and also use for commercial weather obs.

 

Home stations are fabulous for filling in the gaps, but just as long as you know where their "weaknesses" are. I put that in quotes because the "weaknesses" are probably technically accurate readings, but they are not representing larger scale conditions that an ASOS wind sensor or dewpoint reading would.

[CT Rain]

Creepy...we both described AWOS dews as "funky"...lol.

 

lol

 

I love the funky heat index values from the AWOS sites in the summer.

[TWCCraig]

I don't follow ISP dews so I wouldn't know if something stands out, but in general ASOS readings are pretty damn good. I've seen some funky readings with AWOS before though, but of course ISP is ASOS.

Isn't KISP a little bit inland over LI? The more coastal sites factored into the analysis may be bumping up the analysis dew. Also, if ISP radiates well they will probably radiate down to a pretty low tt/td saturation by sunrise. My guess is FOK probably is too low in the eyes of MADIS too.

 

ISP is around the center of the island. I can see how one's sensor would read higher on a summer day if they are closer to the water. ISP radiates pretty well, not as well as FOK, my lows are average a degree higher than ISP because ISP radiates more in the less urbanized environment.

 

One thing regarding the validity of the readings. If most MADIS stations are reporting higher than the ASOS, wouldn't it be reasonable to go with MADIS. Yes some stations are poorly sited, but wouldn't it be more representative of your local neighborhood, like right outside your front door. Not that the ASOS readings are inaccurate, but several hundred years ago, this was all woods, the readings such as dew points would have been higher due to the more evapotranspiration. Having an ASOS sensor out in the open does let it mix more but it's more representative of the area only if most of the area was tree less and exposed.

[CT Rain]

There's a reason that ASOS standards are so high and that we don't use backyard weather stations for most of the input into computer models and also use for commercial weather obs.

 

Home stations are fabulous for filling in the gaps, but just as long as you know where their "weaknesses" are. I put that in quotes because the "weaknesses" are probably technically accurate readings, but they are not representing larger scale conditions that an ASOS wind sensor or dewpoint reading would.

 

Yeah exactly. I bet if you were to put my davis next to the BDL ASOS the readings would be very close. It's siting that's really the issue and since most of us don't have a few square miles of flat grass with no obstructions we don't live in great spots for things like dew point or wind readings.

 

On the other hand... look at the OK Mesonet sites. You can actually compare apples to apples since it's so flat and there are so few obstructions siting is not an issue and the readings can be quite valuable even if the instrumentation is sub-ASOS standards.

[Baroclinic Zone]

Ktan is most definitely not a concrete jungle

[CT Rain]

ISP is around the center of the island. I can see how one's sensor would read higher on a summer day if they are closer to the water. ISP radiates pretty well, not as well as FOK, my lows are average a degree higher than ISP because ISP radiates more in the less urbanized environment.

 

One thing regarding the validity of the readings. If most MADIS stations are reporting higher than the ASOS, wouldn't it be reasonable to go with MADIS. Yes some stations are poorly sited, but wouldn't it be more representative of your local neighborhood, like right outside your front door. Not that the ASOS readings are inaccurate, but several hundred years ago, this was all woods, the readings such as dew points would have been higher due to the more evapotranspiration. Having an ASOS sensor out in the open does let it mix more but it's more representative of the area only if most of the area was tree less and exposed.

 

That's Kevin's argument and that's fine except if you use it in the right context. A 70F dew point in your backyard isn't particularly muggy. A 78 or 79F dew point would be muggy and would probably correspond to a 71 of 72F dew point at KISP.

 

Same thing if you use it for winds. Sandy produced wind gusts over 80 mph at KISP and 60 mph at your local MADIS. Neither reading is incorrect but you can't really compare the 2 numbers since they're apples and oranges.

[CT Rain]

Ktan is most definitely not a concrete jungle

 

BDL too. It's around tabaco fields and a forested ridge line. The only "urbanization" is a few motels, parking lots and fast food joints EAST of the airport. 

 

The ridiculous posts about BDL being like midtown Manhattan crack me up. 

[Mr Torchey]

Yeah they were great Springs, but every spring can't be the best...unless you live in lala land like he does.

I love 60s-70s. Perfect wx,

Every new day is the best day ever, that's how I live my life!

Viva la spring

Viva la life

Viva la viva

Almost miller time another perfect weekend!!!!!!

Doomy gloomy scooty

[dendrite]

AIT, MADIS hates FOK's dews too.

 

http://weather.gladstonefamily.net/site/KFOK

 

Even HWV and FRG are a little low for MADIS's liking.